XE0092-ITR Cermetek Microelectronics, XE0092-ITR Datasheet - Page 3

• Manufacturer Part Number: XE0092-ITR
• Manufacturer: Cermetek Microelectronics

Specifications of XE0092-ITR

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Cermetek Microelectronics, Inc
©2009 Cermetek Microelectronics, Inc.
XE0092 APPLICATION NOTES
Dialing:
The public switched telephone network permits tone
and rotary (pulse) dialing.
both types. Tone dialing requires an external signal
source to generate the dialing tones. The /OH line
on the XE0092 may be pulsed to create pulse
dialing.
Pulse Dialing: The XE0092 generates dialing
pulses through momentary closures of the switch-
hook. Each digit is represented as a series of pulses,
one pulse for a one to ten pulses for a zero. The
pulse rate in North America is ten pulses per second.
The dialing pulses are asymmetrical. The correct
duty cycle in North America is 31 milliseconds on
and 69 milliseconds off. An inter-digit delay of at
least one hundred milliseconds separates the digits.
Tone Dialing: To permit tone dialing the XE0092
seizes the line, /OH active. For each digit a unique
DTMF, Dual Tone Multiple Frequency, tone pair is
applied to TX+ and TX-. The higher frequency tone
is always larger than the lower frequency one.
Transmit the tones for a minimum of 70 milliseconds,
and leave a minimum of 70 milliseconds between
digits.
The following chart shows the correct DTMF signal
frequencies for each digit.
Digit
1
2
3
4
5
6
7
8
9
0
#
*
Lower Tone
697
697
697
770
770
770
852
852
852
941
941
941
Upper Tone
The XE0092 supports
1209
1336
1477
1209
1336
1477
1209
1336
1477
1336
1209
1477
Page 3
Signal Levels:
FCC Part 68 Rules set the allowable signal level in
the US for all signals placed on the telephone line
other than live voice. Other countries have similar
regulations.
Zero dBm is 1 milliwatt through a 600 ohm load.
Distortion:
Distortion is the most common measure of the
quality of the signal path provided by the DAA. The
primary source of this distortion is the line current
holding circuit, although board layout and other
factors can introduce distortion.
Distortion varies with frequency. The voice band of
the telephone line is limited to less than 4000 Hz.
High speed modems such as 33.6K bps and 56K
bps require virtually all of this bandwidth for signal
transmission. Even if the distortion through a device
is good in the center portion of the spectrum, signal
quality is compromised if distortion greatly increases
at the outer limits of the voice band. The XE0092
provides a low distortion signal path across the
entire voice band.
Caller ID Reporting:
The telephone network normally sends the Caller ID
signal between the first and second ring signals. If
the user activates the /CID input while the XE0092 is
off-hook, the Caller ID signal is passed through to
the host through the RX pins on the XE0092. If the
XE0092 is off-hook, /OH low, Caller ID pass-through
cannot be enabled regardless of the state of /CID.
Signal levels are measured in dBm.
Document No. 607-0100 Revision A (10/09)
XE0092 Low-cost DAA Module